BQ3055: Issues with DFF error

Ermanno Antonelli

Part Number: BQ3055

Dear support,

we have some old battery packs BQ3055 based, mostly 20P4S configuration with LiFePO4 cells. We have several on field running fine for several years already.

The issue we're experiencing now is with some shelf spare end customer units, They go in DFF error. Most of those packs battery cells are still ok.

We have different scenarios, some they reset easily sending SMB 00 > word 0057, some needs full PF reset with command SMB 62.

What we can't figure out is that some of the boards even after the above 2 methods don't reset. I even after reload the .senc FW and the golden .GG but they don't get out of the error state.

I have also tried with the 10K resistors method instead of the packs, powering the board 12V with PSU, to isolate packs issues.

Any additional idea.

Thanks, Ermanno

over 3 years ago

0 Ermanno Antonelli over 3 years ago

Prodigy 150 points

>> I should add that in a couple of cases the board is not loading the GG file in the data flash. bqEvWs 0.9.75

0 Kang Kang over 3 years ago in reply to Ermanno Antonelli

TI__Mastermind 24870 points

Hello Ermanno,

Can you attach a gg file and your golden gg file here?

I suggest to compare the two to see if any DF changed where it should not have.

Thanks!

0 Ermanno Antonelli over 3 years ago in reply to Kang Kang

Prodigy 150 points

Attached here.

0250.Archive.zip

0 Kang Kang over 3 years ago in reply to Ermanno Antonelli

TI__Mastermind 24870 points

I didn't see any DF content that looked out of place.

Do you have a reliable method to reproduce this?

0 Ermanno Antonelli over 3 years ago in reply to Kang Kang

Prodigy 150 points

Hi Kang Kang,

that's what I thought too. The error is very difficult to reproduce and it happened at customer spare stock units, meaning that they might have been on shelf without power cycling for a while.

I have 2 questions to help me debug the issue:

1) what can be the source of a permanent DFF, other than the BQ chip damaged?

2) Is there a specific procedure to clear a permanent DFF error other than the one I used above?

Thanks

0 Kang Kang over 3 years ago in reply to Ermanno Antonelli

TI__Mastermind 24870 points

Hello Ermanno,

1. DFF just means our DF checksum does not match the DF checksum computed by the gauge. Can you send me the srec or senc files using EVSW, I can look at the entire DF image compared to the entire golden DF image.

2. Let's make sure we look at the entire DF map prior to making this decision.

0 Ermanno Antonelli over 3 years ago in reply to Kang Kang

Prodigy 150 points

I have attached here the original senc and the downloaded one from EVsw, form one of my boards I have here where I can make more debugging.

Cheers, E.senc files.zip

0 Kang Kang over 3 years ago in reply to Ermanno Antonelli

TI__Mastermind 24870 points

Thanks, give me until Friday. I will compare the files and let you know what I find.

0 Ermanno Antonelli over 3 years ago in reply to Kang Kang

Prodigy 150 points

Any news on this?

0 Kang Kang over 3 years ago in reply to Ermanno Antonelli

TI__Mastermind 24870 points

Hello Ermanno,

I didn't find any irregularities.

Can you try to reproduce this in a lab setting?

0 Ermanno Antonelli over 3 years ago in reply to Kang Kang

Prodigy 150 points

Hi Kang Kang,

despite the many tests, I wasn't able to reproduce the problem.

Another question still remain open, how to reset this error?

Even with the 4 packs disconnected and replaced with simulation resistors and bench-top PSU, we're not able to reset the fault?

Reloaded golden FW, I sent you, the .GG is simply ignored.

I can only assume a permanent failure of the internal flash.

Thanks, E.

0 Wyatt Keller over 3 years ago in reply to Ermanno Antonelli

TI__Guru** 103155 points

Hello Ermanno,

DFF indicates a bad checksum, for example gauge tried to write “1” in a physical cell memory but memory cell can’t not hold enough charge to represent “1” and it is read as “0” and that cannot be changed by PF Clear command. Other way is some kind of ESD has corrupted the flash memory.

Sincerely,

Wyatt Keller

0 Ermanno Antonelli over 3 years ago in reply to Wyatt Keller

Prodigy 150 points

Thanks Wyatt, I think we can close this and consider the BQ defective.

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BQ3055: Issues with DFF error